An alternative practice style
I have never really liked counting laps because it requires some of my focus to keep a count going, and as I have gotten faster, I can usually do 2500-3000+ yards in an hour which is 100-120 laps to keep track of.
Because I can more easily remember things like: practice for 10 minutes, I simply divide the practice into 10 minute segments and practice one thing for that. I find that this helps me in two ways: it improves my focus because I only have one thing to think about (if I go over 10 minutes, that is actually good), and it helps me keep at drills even when I would normally have been bored.
Here are two sample practices from my swim notebook (each item is meant to be swum for 10 minutes):
* Freestyle technique practice *
Dolphin (I swim these sculling facedown, and sideways)
Stroke counting at 1.1s (with tempo timer)
Balance and flipturns (zenswitch with fast flipturns)
* Butterfly technique practice *
Dolphin (mostly sculling dolphin)
Ride the wave